Directional solidification casting assembly and method

ABSTRACT

A directional solidification casting method includes fluidly coupling a feed line conduit with a source of molten metal and with a directional solidification mold at a gating. The mold has an interior chamber with a shape of an object to be cast using directional solidification in a growth direction. The feed line conduit is fluidly coupled with the gating in a downward direction oriented at an angle that is closer to the growth direction of the mold than to another direction that is perpendicular to the growth direction of the mold. The method also includes positioning a downstream portion of the feed line conduit below the gating, directing the molten metal into the mold via the feed line conduit, and casting the object in the mold using directional solidification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/280,249 (filed 26 Mar. 2021), which is a national stage applicationfiled pursuant to 35 U.S.C. § 371 of International Patent ApplicationNo. PCT/US2018/056085 (filed 16 Oct. 2018). The entire disclosures ofthese application are incorporated herein by reference.

BACKGROUND Technical Field

The subject matter described herein relates to casting assemblies usedto manufacture directionally solidified metal components.

State of the Art

Many components can be formed using directional solidificationtechniques. Directional solidification (DS) techniques enable thesolidification of materials with grains aligned in a specific direction.Directional and single crystal structures can be created to improve themechanical and metallurgical properties of the cast materials. Thesestructures can be produced by casting a melt of an alloy. Heat transferconditions during solidification of the casting are controlled so that asolidification front advances along a growth direction to generateprimary columnar crystals or grains and to avoid or reduce nucleation ofsecondary grains from the melt.

Directional solidification is not, however, without drawbacks. Someknown directional solidification casting assemblies include a straightor linear feed line that directs molten metal into a mold via a gatingbetween the feed line and the mold. It has been found by the inventorsof this application that these straight feed lines often result in straymetal grains propagating into the mold from the feed line. These straygrains can emerge from the junction between the gating and the mold andinto the component being cast in the mold. The stray grains interruptformation of the single or columnar crystal structure being formed inthe mold. For cast objects having low thresholds for such crystalfaults, these stray grains can result in a large percentage of theobjects being unusable. For example, the inventors have found that useof a straight feed line for the single crystal formation of the bladesof turbine engine airfoils has resulted in unacceptable failure rates.

BRIEF DESCRIPTION

In one example, a directional solidification casting method includesfluidly coupling a first open end of a feed line conduit with acontainer source of a molten metal, and fluidly coupling an opposite,second open end of the feed line conduit with a directionalsolidification mold at a gating of the mold. The mold has an interiorchamber with a shape of an object to be cast using directionalsolidification of the molten metal in a growth direction of the mold.The feed line conduit is fluidly coupled with the gating in a downwarddirection oriented at an angle that is closer to the growth direction ofthe mold than to another direction that is perpendicular to the growthdirection of the mold. The method also includes positioning at least adownstream portion of the feed line conduit below the gating of the moldalong the growth direction. The downstream portion of the feed lineconduit extends between the second open end of the feed line conduit andan intermediate location in the feed line conduit between the first andsecond open ends. The method also includes directing the molten metalinto the mold via the feed line conduit and casting the object in themold using directional solidification.

In another example, a directional solidification casting assemblyincludes a directional solidification mold having an interior chamberwith a shape of an object to be cast using directional solidification ofmolten metal in a growth direction of the mold, and a feed line conduithaving a length that extends from a first open end to a second open end.The first open end of the feed line conduit is fluidly coupled with acontainer source of the molten metal. The second open end of the feedline conduit is fluidly coupled with the mold at a gating, the feed lineconduit configured to convey the molten metal into the mold through thegating for directional solidification of the object to be cast in themold. The feed line conduit connects with the gating in a downwarddirection that is oriented at an angle that is closer to the growthdirection than to another direction that is perpendicular to the growthdirection.

In another example, a directional solidification casting assemblyincludes a directional solidification mold having an interior chamberwith a shape of an object to be cast using directional solidification ofmolten metal along a growth direction of the mold and a feed lineconduit configured to be fluidly coupled with a container source of themolten metal and with the mold. The feed line conduit is connected withthe mold along a downward direction that is oriented closer to thegrowth direction of the mold than along another direction that isperpendicular to the growth direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one example of a directional solidification castingassembly.

FIG. 2 illustrates another example of a directional solidificationcasting assembly.

FIG. 3 schematically illustrates one example of operation of the castingassembly shown in FIG. 1 without a bend in the feed line conduit shownin FIG. 2 .

FIG. 4 is a photograph of a portion of an object cast using the castingassembly shown in FIG. 1 .

FIG. 5 is a photograph of a portion of an object cast using the castingassembly shown in FIG. 2 .

FIG. 6 illustrates a directional solidification casting assemblyaccording to another embodiment.

FIG. 7 illustrates a flowchart of one embodiment of a method for castingan object using directional solidification.

DETAILED DESCRIPTION

The inventive subject matter described herein relates to a directionalsolidification casting assembly and method that reduces the frequency ofstray grains in single crystal castings. The casting assembly modifiesthe known feed line geometry from a straight channel to one in which thechannel first drops below a joint between the feed line and the mold orthe object being cast in the mold (e.g., this joint can be referred toas the gating) before rising to the level of the gating. This drop andrising creates a U-shaped bend in the feed line. During the directionalcasting, the molten metal in the bottom of the feed line solidifiesbefore the gating into the blade, and thus further flow of molten metalfrom the feed line upstream of the U-bend into the mold is prevented.This solidification and resultant prevention of additional flow ofmolten metal can prevent stray grains from forming in the feed line orgating and then entering the mold (and object being cast in the mold).

Optionally, the casting assembly can have the feed line attached to themold (e.g., object being cast, or continuator) at an angle that is closeto vertical such that grains grow from the object being cast in the mold(e.g., the turbine blade) into the feed line, rather than vice versa.

FIG. 1 illustrates one example of a directional solidification castingassembly 100. The casting assembly 100 includes a feed line conduit 102that defines a channel through which molten metal flows from a container(not shown) into an interior chamber of a mold 104. The feed lineconduit 102 is fluidly coupled with the interior of the mold 104 at agating 106. In operation, molten metal flows from the container and intothe mold 104 through the feed line conduit 102. The molten metal isdirectionally solidified within the mold 104 along a growth direction108 to form a single crystal or columnar crystal (e.g., several crystalgrains aligned in vertical columns along the growth direction 108).

As shown, the feed line conduit 102 is predominantly oriented along astraight line into the mold 104 via the gating 106. While the feed lineconduit 102 may have a slight bend or curve, the feed line conduit 102is angled downward from the container from which the molten metal issupplied to the gating 106 (relative to the vertical or growth direction108). This orientation results in the molten metal always flowingdownward or downhill from the container source of the molten metalthrough feed line conduit 102 to the gating 106 of the mold 104. Duringsolidification of the molten metal, some of the metal in the feed lineconduit 102 can begin to solidify while the metal in the mold 104solidifies. For a single crystal configuration, the mold 104 may includeor be fluidly coupled with a seed crystal grain and a helical grainselector (not shown) beneath the mold 104. For a columnar grainconfiguration, the mold may include a chamber in which a columnar grainstructure can be developed (often known as a starter block).

The metal in the feed line conduit 102 also can solidify and form one ormore grains. The grains formed in the feed line conduit 102 are verylikely not oriented in the same direction(s) as the crystalline grainsformed in the mold 104 due to the grains formed in the feed line conduit102 not growing from the same seed crystal or pig tail channel as themetal in the mold 104. As described above, this orientation of the feedline conduit 102 can result in metal containing stray grains formed inthe feed line conduit 102 flowing into the mold 104 and/or the flow ofthe metal breaking off tips of dendrites that are solidifying in themold 104. Either of these scenarios can disrupt the growth of the singlecrystal columnar structure being formed in the mold 104 and canintroduce stray grains into the mold 104. The stray grains can formweaker locations in the cast objects and can result in the objects beingunable to be used. For example, some turbine blades cannot have straygrains due to the introduction of mechanical weakness at the straygrains.

FIG. 2 illustrates another example of a directional solidificationcasting assembly 200. The casting assembly 200 includes a container 202that holds the molten metal and operates as a source of the metal forthe casting process. The casting assembly 200 also includes the feedline conduit 102, the mold 104, and the gating 106. The feed lineconduit 102 includes open ends 204, 206 at opposite ends of the lengthof the feed line conduit 102. One open end 204 fluidly couples the feedline conduit 102 with the container 202 so that the feed line conduit102 can receive the molten metal from the container 202. The other openend 206 of the feed line conduit 102 fluidly couples the feed lineconduit 102 with the gating 106 of the mold 104. As described above, thefeed line conduit 102 conveys or directs the molten metal from thecontainer 202 to the mold 104 for directional solidification of theobject to be cast in the mold 104.

For a single crystal configuration, the mold 104 may include or befluidly coupled with a seed crystal grain and a grain selector (notshown) beneath the mold 104. For a columnar grain configuration, themold may include a chamber in which a multiple columnar grain structurecan be developed (often known as a starter block).

One difference between the casting assembly 100 shown in FIG. 1 and thecasting assembly 200 shown in FIG. 2 is the shape of the feed lineconduit 102. As shown in FIG. 2 , the feed line conduit 102 has a convexU-bend 208 (e.g., convex relative to the growth direction 108). ThisU-bend 208 is located at or includes an intermediate location 210 of thefeed line conduit 102 that is located between the ends 204, 206 of thefeed line conduit 102. Optionally, the intermediate location 210 can beat the middle location or midway point along the length of the feed lineconduit 102 from one end 204 or 206 to the other end 206 or 204 of thefeed line conduit 102. Alternatively, the intermediate location 210 canbe closer to the end 204 or 206 than the other end 206 or 204 of thefeed line conduit 102.

The U-bend 208 in the feed line conduit 102 is formed by an upstreamportion 212 of the feed line conduit 102 extending in a downwarddirection from the end 204 to the intermediate location 210 and by adownstream portion 214 of the feed line conduit 102 extending in anupward direction from the intermediate location 210 toward the gating106 of the mold 104 (to which the end 206 of the feed line conduit 102is coupled). The downstream portion 214 and the upstream portion 212 ofthe feed line conduit 102 are both located above the bend in the feedline conduit 102 along the growth direction 108. In the illustratedembodiment, the downstream end 206 of the feed line conduit 102 is abovethe gating 106 of the mold 104 and the upstream end 204 of the feed lineconduit 102 is above the downstream end 206 of the feed line conduit 102and (optionally) the gating 106 of the mold 104.

This shape of the feed line conduit 102 causes the molten metal to flowdownward in the upstream portion 212 of the conduit 102 from thecontainer 202 to the intermediate location 210, then upward through thedownstream portion 214 of the conduit 102 to a downstream peak location218 that is at the end of the downstream portion 214 and upstream of theend 206 that couples with the gating 106. The molten metal then flowsdown the conduit 102 from the peak location 218, through the gating 106,and into the mold 104 to be directionally solidified along the growthdirection 108 in the mold 104 to form a cast object.

The gating 106 may be a rigid or semi-rigid body (e.g., flexible, butstiff enough that the body breaks or is irreparably damaged if bent toofar). The gating 106 can be oriented in an upward angle relative to thelength of the mold 104 or the growth direction 108. For example, thegating 106 may be oriented such that the force of gravity would pull themolten metal down through the gating 106 into the mold 104 and the anglebetween the direction in which the gating 106 is elongated and thegrowth direction 108 is less than forty-five degrees or is less thanthirty degrees. The peak location 218 of the feed line conduit 102 maybe the location in the conduit 102 to which the gating 106 extendsinside the feed line conduit 102 or may be the location that is forcedto bend downward so that the feed line conduit 102 can mate with thegating 106. This connection can cause the feed line conduit 102 toconnect with the gating 106 in a downward direction that is oriented atan angle closer to the growth direction 108 than to a direction that isperpendicular to the growth direction 108. For example, the angle atwhich the feed line conduit 102 is oriented at the gating 106 may bewithin forty-five degrees of the growth direction 108.

In the illustrated embodiment, an anchor 216 is coupled with the feedline conduit 102. The feed line conduit 102 can be formed of a flexiblematerial, such as wax, or the like. The feed line conduit 102 may needto be held in more rigid manner to ensure that the U-bend 208 does notflex during a subsequent shelling operation. The anchor 216 is a bodythat holds the conduit 102 in a more rigid way, The anchor 216 can be anelongated pole, pipe, or the like, that is connected with the feed lineconduit 102 on one end of the anchor 216 and the ground or anothersurface beneath the feed line conduit 102 on the opposite end of theanchor 216. For example, the anchor 216 can hold the shape of the U-bend208 in the feed line conduit 102, while the opposite ends 204, 206 ofthe feed line conduit 102 are coupled with locations (e.g., thecontainer 202 and the gating 106) in locations that are above theintermediate location 210. Alternatively, the assembly 200 does notinclude the anchor 216. For example, the conduit 102 may be formed of arigid material that maintains the U-bend 208 in the conduit 102.

Use of the U-bend 208 in the feed line conduit 102 reduces or eliminatesthe formation of stray grains growing in the object that is cast in themold 104. As described above, stray grains can be metal crystals that donot have the same crystalline structure and/or have the same crystallinestructure that is oriented in another direction as the grains that growfrom a seed crystal in the mold 104. Introducing the U-bend 208 into thefeed line conduit 102 can reduce or eliminate the entry of stray grainsinto the mold 104 from the conduit 102 or gating 106 as the molten metalflows from the container 202 into the mold 104 via the conduit 102 andthe gating 106, as the metal contacts the seed crystal, and as the metalbegins to cool and grow crystalline grains in the growth direction 108within the mold 104.

FIG. 3 schematically illustrates one example of operation of the castingassembly 100 without the U-bend 208 in the feed line conduit 102. Duringcasting of the object in the mold 104 without the bend 208 in the feedline conduit 102, molten metal 300 flows into the bottom of the mold 104and solidifies along a solidification front 302. This solidificationfront 302 is formed of columns or dendrites 312 of crystalline grainsthat move or grow along the growth direction 108 into a core 304 of themold 104.

In one embodiment, as the solidification front 302 moves past a joint306 between the mold 104 and the feed line conduit 102 and an object 310being cast in the mold 104, molten metal 300 may continue to flow 322from the molten portion of the object 310 (e.g., inside the mold 104)and to flow 300 from the feed line conduit 102 to accommodatesolidification and thermal shrinkage of the metal. If the liquid flowrate of the molten metal 300 coming from the feed line conduit 102 isgreater than the liquid flow rate of the molten metal 322 from theobject 310 (e.g., from inside the mold 104 to out into the feed lineconduit 102 along directions 322 shown in FIG. 3 ), then a portion 320of the liquid metal 300 may flow around the joint 306, break of the tipsof the dendrites 312 and redeposit the broken tips on the surface of theobject 310 being cast. This may introduce stray grains into the object310 and can create a freckle chain in the grains.

Conversely, introducing the downward bend 208 in the feed line conduit102 as shown in the assembly 200 can prevent this stray grainintroduction into the object 310. The downward bend 208 causes themolten metal 300 in the feed line conduit 102 (e.g., within the bend208) to solidify in the feed line conduit 102 after the molten metalfills the mold 104, but before the solidification front moves across thegating 106. This prevents further flow of the molten metal 300 from thefeed line conduit 102 into the mold 104, which stops or reduces the flowof molten metal 300 around the joint 306 and into the object 310. Thishas been found to stop the generation of freckles in the object 310,which indicates that stray grains are not being introduced into theobject 310.

FIGS. 4 and 5 are photographs of a portion of objects 410, 510 beingcast using the casting assembly 100 (shown in FIG. 1 ) and the castingassembly 200 (shown in FIG. 2 ). The object 410 is part of a turbineblade that was cast in the mold 104 using the feed line conduit 102 ofthe casting assembly 100 that did not include the bend 208 in the feedline conduit 102. The object 510 is the same part of another turbineblade that was cast in the mold 104 using the feed line conduit 102 ofthe casting assembly 200 that did include the bend 208 in the feed lineconduit 102.

As shown, the object 410 includes freckles 400 just below a gating 308or connection between the mold 104 and the gating 106, while the object510 does not have these freckles 400. The presence of the freckles 400indicates that the object 410 includes stray grains in the crystallinestructure of the object 410, while the absence of the freckles 400 fromthe object 510 indicates that the object 510 may not have stray grainsin the crystalline structure of the object 510 at or near the gating308. An object 410 having the freckles 400 may be discarded and not putinto use (e.g., is not included in a turbine engine). Therefore,reducing or eliminating the freckles 400 and stray grains can reduce theamount of material and parts that are discarded.

FIG. 6 illustrates a directional solidification casting assembly 600according to another embodiment. The casting assembly 600 includes thecontainer 202 of molten metal, the gating 106, and the mold 104described above. Optionally, the casting assembly 600 can include one ormore additional components, such as the pig tail channel 220. Thecasting assembly 600 also includes a feed manifold 606 located beneaththe gating 106 of the mold 104. An upstream feed line conduit 602fluidly couples the container 202 with the manifold 606 so that themolten metal can flow from the container 202 into the manifold 606. Themanifold 606 can include one or more internal channels to direct themolten metal into and up through a downstream feed line conduit 604 thatis fluidly coupled with the upstream feed line conduit 602.

The downstream feed line conduit 604 also can be fluidly coupled withthe gating 106 and the mold 104. The downstream feed line conduit 604directs the molten metal into the mold 104 through the gating 106 tocast the object in the mold 104. As shown, the manifold 606 can belocated below or lower than the gating 106 to prevent the flow of straygrains into the object being cast from the conduit 604. The downstreamfeed line conduit 604 can be coupled with the gating 106 at an uprightangle or position (e.g., closer to a vertical orientation than ahorizontal orientation, as shown in FIG. 6 ). This can help preventmolten metal from continuing to flow across the solidification front inthe mold 104 due to the molten metal first solidifying beneath thegating 106 and/or not being able to flow uphill and into the mold 104through the gating 106. For example, the molten metal 300 in thedownstream feed line conduit 604 can solidify after the molten metalfills the mold 104, but before the solidification front moves across thegating 106. As described above, this prevents further flow of the moltenmetal 300 from the downstream feed line conduit 604 into the mold 104,which stops or reduces the flow of molten metal 300 around the joint 306and into the object being cast in the mold.

FIG. 7 illustrates a flowchart of one embodiment of a method 700 forcasting an object using directional solidification. The method 700 canuse one or more of the casting assemblies described herein or can beused with another casting assembly. At 702, a feed line conduit isfluidly coupled with a container or other source of molten metal. Forexample, one open end of the conduit can be connected with an openinginto the container or other source. At 704, the feed line conduit isfluidly coupled with a gating of a mold. The feed line conduit can beconnected with the gating such that the portion of the feed line conduitthat mates with the gating is vertically oriented or close to a verticalorientation. For example, the portion of the feed line conduit thatmates with the gating can be oriented at an angle that is less thanthirty degrees from a vertical direction (relative to the direction ofgravity).

At 706, at least a downstream portion of the feed line conduit isoriented upward toward or to the gating of the mold. For example, aconvex bend may be formed in the feed line conduit (with or without useof an anchor) such that one portion of the feed line conduit thatextends to another portion of the feed line conduit (that mates with thegating) extends upward (and not downward or horizontally).Alternatively, the entire feed line conduit can extend from a manifoldlocated below the gating up to the gating.

At 708, molten metal is directed into the mold from the containerthrough the feed line conduit. The molten metal can be pumped throughthe feed line conduit and/or can flow through the feed line conduit dueto gravity. The molten metal may begin solidifying in the mold with asolidification front moving in the mold in an upward or verticaldirection. A cooling plate may be positioned beneath the mold to causethe solidification front to move upward. At 710, flow of the moltenmetal through the feed line stops or slows prior to the solidificationfront growing past and crossing the gating of the mold. (For example,the flow rate of metal from the feed line conduit can slow down to beslower than the flow rate of metal from the molten portion of the objectbeing cast in the mold. As described above, stopping the flow of themolten metal in the feed line conduit prior to the solidification frontpassing the gating can prevent stray grains from forming in the objectbeing cast in the mold.

In one embodiment, a directional solidification casting assembly isprovided. The assembly includes a container source of a molten metal, adirectional solidification mold having an interior chamber with a shapeof an object to be cast using directional solidification of the moltenmetal in a growth direction of the mold, and a feed line conduit havinga length that extends from a first open end to a second open end with anintermediate location between the first and second open ends. The firstopen end of the feed line conduit is fluidly coupled with the containersource. The second open end of the feed line conduit is fluidly coupledwith the mold at a gating. The feed line conduit is configured to conveythe molten metal into the mold through the gating for directionalsolidification of the object to be cast in the mold. At least adownstream portion of the feed line conduit that is between theintermediate location of the feed line conduit and the second open endof the feed line conduit is located below the gating along the growthdirection of the mold. Optionally, the assembly does not include thecontainer source of the metal, but is fluidly coupled with thiscontainer source.

Optionally, the mold is configured to receive the molten metal fordirectionally solidifying the object as one or more of a single crystalgrain structure or a columnar crystal structure in the mold.

Optionally, the feed line conduit has a bend in the length of the feedline conduit such that the downstream portion of the feed line conduitand an upstream portion of the feed line conduit between the first openend and the bend are both located above the bend in the feed lineconduit along the growth direction.

Optionally, the assembly also includes an anchor coupled with the feedline conduit at the intermediate location and configured to hold theintermediate location of the feed line conduit below the first andsecond open ends of the feed line conduit along the growth direction.

Optionally, the downstream portion of the feed line conduit is angledupward toward the gating along the growth direction of the mold.

Optionally, the feed line conduit connects with the gating in a downwarddirection that is oriented at an angle that is closer to the growthdirection than to a direction that is perpendicular to the growthdirection.

Optionally, the feed line conduit connects with the gating at an anglethat is within thirty degrees of the growth direction.

In one embodiment, a directional solidification casting method isprovided. The method includes fluidly coupling a first open end of afeed line conduit with a container source of a molten metal and fluidlycoupling an opposite, second open end of the feed line conduit with adirectional solidification mold at a gating of the mold. The mold has aninterior chamber with a shape of an object to be cast using directionalsolidification of the molten metal in a growth direction of the mold.The method also includes positioning at least a downstream portion ofthe feed line conduit below the gating of the mold along the growthdirection. The downstream portion of the feed line conduit extendsbetween the second open end of the feed line conduit and an intermediatelocation in the feed line conduit between the first and second openends. The method also includes directing the molten metal into the moldvia the feed line conduit and casting the object in the mold usingdirectional solidification.

Optionally, casting the object includes directionally solidifying theobject as one or more of a single crystal grain structure or a columnarcrystal structure in the mold.

Optionally, positioning the feed line conduit includes forming a bend inthe length of the feed line conduit such that the downstream portion ofthe feed line conduit and at least an upstream portion of the feed lineconduit are both located above the bend in the feed line conduit alongthe growth direction. The upstream portion of the feed line conduit canbe located between the first open end and the bend.

Optionally, the method also includes coupling an anchor with the feedline conduit at the intermediate location. The anchor can hold theintermediate location of the feed line conduit below the first andsecond open ends of the feed line conduit along the growth direction.

Optionally, the downstream portion of the feed line conduit is angledupward toward the gating along the growth direction of the mold.

Optionally, the feed line conduit connects with the gating in a downwarddirection that is oriented at an angle that is closer to the growthdirection than to a direction that is perpendicular to the growthdirection.

Optionally, the feed line conduit connects with the gating at an anglethat is within thirty degrees of the growth direction.

In one embodiment, a directional solidification casting assembly isprovided. The assembly includes a directional solidification mold havingan interior chamber with a shape of an object to be cast usingdirectional solidification of molten metal in a growth direction of themold and a feed line conduit having a length that extends from a firstopen end to a second open end. The first open end of the feed lineconduit is fluidly coupled with the container source. The second openend of the feed line conduit is fluidly coupled with the mold at agating. The feed line conduit is configured to convey the molten metalinto the mold through the gating for directional solidification of theobject to be cast in the mold. The feed line conduit connects with thegating in a downward direction that is oriented at an angle that iscloser to the growth direction than to a direction that is perpendicularto the growth direction.

Optionally, the feed line conduit connects with the gating at an anglethat is within thirty degrees of the growth direction.

Optionally, at least a downstream portion of the feed line conduit thatis between an intermediate location of the feed line conduit and thesecond open end of the feed line conduit is located below the gatingalong the growth direction of the mold.

Optionally, the mold is configured to receive the molten metal fordirectionally solidifying the object as a single crystal grain structurein the mold.

Optionally, the feed line conduit has a bend in the length of the feedline conduit such that the downstream segment of the feed line conduitand an upstream portion of the feed line conduit between the first openend and the bend are both located above the bend in the feed lineconduit along the growth direction.

Optionally, the assembly also includes an anchor coupled with the feedline conduit at the intermediate location and configured to hold theintermediate location of the feed line conduit below the first andsecond open ends of the feed line conduit along the growth direction.

Optionally, the downstream portion of the feed line conduit is angledupward toward the gating along the growth direction of the mold.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventivesubject matter without departing from its scope. While the dimensionsand types of materials described herein are intended to define theparameters of the inventive subject matter, they are by no meanslimiting and are exemplary embodiments. Many other embodiments will beapparent to one of ordinary skill in the art upon reviewing the abovedescription. The scope of the inventive subject matter should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects. Further, thelimitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

This written description uses examples to disclose several embodimentsof the inventive subject matter to enable one of ordinary skill in theart to practice the embodiments of inventive subject matter, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the inventive subject matter is definedby the claims, and may include other examples that occur to one ofordinary skill in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

The foregoing description of certain embodiments of the presentinventive subject matter will be better understood when read inconjunction with the appended drawings. The various embodiments are notlimited to the arrangements and instrumentality shown in the drawings.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“comprises,” “including,” “includes,” “having,” or “has” an element or aplurality of elements having a particular property may includeadditional such elements not having that property.

What is claimed is:
 1. A directional solidification casting method, themethod comprising: fluidly coupling a first open end of a feed lineconduit with a container source of a molten metal; fluidly coupling anopposite, second open end of the feed line conduit with a directionalsolidification mold at a gating of the mold, the mold having an interiorchamber with a shape of an object to be cast using directionalsolidification of the molten metal in a growth direction of the mold,the feed line conduit fluidly coupled with the gating in a downwarddirection oriented at an angle that is closer to the growth direction ofthe mold than to another direction that is perpendicular to the growthdirection of the mold; positioning at least a downstream portion of thefeed line conduit below the gating of the mold along the growthdirection, the downstream portion of the feed line conduit extendingbetween the second open end of the feed line conduit and an intermediatelocation in the feed line conduit between the first and second openends; directing the molten metal into the mold via the feed lineconduit; and casting the object in the mold using directionalsolidification.
 2. The method of claim 1, wherein casting the objectincludes directionally solidifying the object as one or more of a singlecrystal grain structure or a columnar crystal structure in the mold. 3.The method of claim 1, wherein positioning the feed line conduitincludes forming a bend in the feed line conduit such that thedownstream portion of the feed line conduit and at least an upstreamportion of the feed line conduit are both located above the bend in thefeed line conduit along the growth direction, wherein the upstreamportion of the feed line conduit is located between the first open endand the bend.
 4. The method of claim 1, further comprising: coupling ananchor with the feed line conduit at the intermediate location, whereinthe anchor holds the intermediate location of the feed line conduitbelow the first and second open ends of the feed line conduit along thegrowth direction.
 5. The method of claim 1, wherein the downstreamportion of the feed line conduit is angled upward toward the gatingalong the growth direction of the mold.
 6. The method of claim 1,wherein the feed line conduit connects with the gating at an angle thatis within thirty degrees of the growth direction.
 7. A directionalsolidification casting assembly comprising: a directional solidificationmold having an interior chamber with a shape of an object to be castusing directional solidification of molten metal in a growth directionof the mold; and a feed line conduit having a length that extends from afirst open end to a second open end, the first open end of the feed lineconduit fluidly coupled with a container source of the molten metal, thesecond open end of the feed line conduit fluidly coupled with the moldat a gating, the feed line conduit configured to convey the molten metalinto the mold through the gating for directional solidification of theobject to be cast in the mold, wherein the feed line conduit connectswith the gating in a downward direction that is oriented at an anglethat is closer to the growth direction than to another direction that isperpendicular to the growth direction.
 8. The directional solidificationcasting assembly of claim 7, wherein the feed line conduit connects withthe gating at an angle that is within thirty degrees of the growthdirection.
 9. The directional solidification casting assembly of claim7, wherein at least a downstream portion of the feed line conduit thatis between an intermediate location of the feed line conduit and thesecond open end of the feed line conduit is located below the gatingalong the growth direction of the mold.
 10. The directionalsolidification casting assembly of claim 7, wherein the mold isconfigured to receive the molten metal for directionally solidifying theobject as a single crystal grain structure in the mold.
 11. Thedirectional solidification casting assembly of claim 7, wherein the feedline conduit has a bend in the length of the feed line conduit such thata downstream segment of the feed line conduit and an upstream portion ofthe feed line conduit between the first open end and the bend are bothlocated above the bend in the feed line conduit along the growthdirection.
 12. The directional solidification casting assembly of claim7, further comprising: an anchor coupled with the feed line conduit atan intermediate location of the feed line conduit and configured to holdthe intermediate location of the feed line conduit below the first andsecond open ends of the feed line conduit along the growth direction.13. The directional solidification casting assembly of claim 7, whereina downstream portion of the feed line conduit is angled upward towardthe gating along the growth direction of the mold.
 14. A directionalsolidification casting assembly comprising: a directional solidificationmold having an interior chamber with a shape of an object to be castusing directional solidification of molten metal along a growthdirection of the mold; and a feed line conduit configured to be fluidlycoupled with a container source of the molten metal and with the mold,the feed line conduit connected with the mold along a downward directionthat is oriented closer to the growth direction of the mold than alonganother direction that is perpendicular to the growth direction.
 15. Thedirectional solidification casting assembly of claim 14, wherein thefeed line conduit is coupled with the mold at a gating of the mold. 16.The directional solidification casting assembly of claim 14, wherein thefeed line conduit connects with the mold at an angle that is withinthirty degrees of the growth direction.
 17. The directionalsolidification casting assembly of claim 14, wherein the feed lineconduit includes a downstream portion between an intermediate locationof the feed line conduit and an open end of the feed line conduit thatconnects with the mold, the downstream portion of the feed line conduitis located below a location where the feed line conduit connects withthe mold along the growth direction of the mold.
 18. The directionalsolidification casting assembly of claim 14, wherein the mold isconfigured to receive the molten metal for directionally solidifying theobject as a single crystal grain structure in the mold.
 19. Thedirectional solidification casting assembly of claim 14, wherein thefeed line conduit has a bend such that (a) a downstream segment of thefeed line conduit that is closer to the mold than the container sourceand (b) an upstream portion of the feed line conduit that is closer tothe container source than the mold are both located above the bend inthe feed line conduit along the growth direction.
 20. The directionalsolidification casting assembly of claim 14, further comprising: ananchor coupled with the feed line conduit at an intermediate location ofthe feed line conduit, the anchor configured to hold the intermediatelocation of the feed line conduit below opposite open ends of the feedline conduit along the growth direction.